If your USB stick shows up as a drive - e.g Drive G: - it should be possible to install to it. However, that doesn't make it a run-time piece of software, since Windows require the software to be installed into it's registry to be able to use it.

But I suppose you could copy the entire disc-image onto a USB stick so that you can install the software on any PC you jack it into. that may not be in keeping with your license-agreement (not sure how Adobe keeps track of that - issue would be with online activation of a new install perhaps).